The party line I heard was that Glock recently landed a couple of big gov't contracts and would be filling those before they would be producing for the GP. The model in question in my case was the G23.
While this may be the case, there are still plenty of them available at the gun shows.
Some of that stuff is said to entice you to "buy now, cause we don't know when we will be getting any more."
By the way, I did buy one, and it hasn't blown up yet...yes I have shot it.